1. Progress in Understanding a. Monitoring of sea measurement methods and results Readings of Sea Area Monitoring by Japan 3, Oct., 2011 Masanao NAKANO Japan Atomic Energy Agency 1 （C） JAMSTEC

Contents 1.Organization 2.Monitoring plan by Japanese government 3.Sampling, analysis, measurement 4.Radioactivity concentration in seawater and seabed sediment 5.Plan for future marine monitoring 2

1. Organization 3 MERIJAMSTEC JAEA JCAC TEPCO Nuclear Emergency Response Headquarters NISAFA [government] MEXT: Ministry of Education, Culture, Sports, Science and Technology METI: Ministry of Economy, Trade and Industry FA: Fisheries Agency JCG: Japan Coast Guard(sampling) [incorporated foundation] MERI: Marine Ecology Research Institute (sampling) JCAC: Japan Chemical Analysis Center (analysis) KEEA ： Kyusyu Environmental Evaluation Association(analysis) [incorporated administrative agency] FRA: Fisheries Research Agency(sampling) JAMSTEC: Japan Agency for Marine-Earth Science and Technology (sampling) JAEA: Japan Atomic Energy Agency (analysis) [incorporated company] TEPCO: The Tokyo Electric Power Company, Incorporated (sampling, analysis) FRA Sampling Coordination Analysis Prefecture Fukushima, Ibaraki, etc. KEEA JCG

2. Monitoring plan by Japanese government 4 DatePlan March 22Sea Area Monitoring Action Plan April 5Enhancement of Sea Area Monitoring April 25Strengthening of Sea Area Monitoring May 6Sea Area Monitoring in Wider Areas August 2Comprehensive Monitoring Plan Near field + Far field Gamma emitter + Sr, Pu High frequency Low frequency Higher detection limit lower limit (1) Radioactivity concentrations in the seawater (2) Air dose rates over the sea (3) Radioactivity concentrations in airborne dust over the sea

3. Sampling, analysis, measurement Main sampling location a) Front of NPP site (By TEPCO) b) Near(~20km) site (By TEPCO) c) About 30 km from site (By JAMSTEC) d) + Neighbor prefecture (by MERI) (~150km north and south from NPP) e) Deep sea (by JAMSTEC & FRA) 5 a) b) d) c) e) （C） JAMSTEC

Seawater sampling Sediment sampling Airborne sampling Dose measurement 6 Pictures taken by MERI

Instrumental analysis for gamma nuclide in seawater sample By Japan Atomic Energy Agency Taking aliquot of sample Measurement for 3600 second by gamma ray spectrometer (for 1000 sec by TEPCO) Analysis Special beaker for measurement (Marinelli beaker) 7

8 CL:concentration limit （ Bq/cm 3 ） i:age DC(i):dose coefficient for the age i （ mSv/Bq ） WI(i):water ingestion for the age i （ cm 3 /y ） Annihilation 511 K-40 Bi-214 Pb-214 Cs-134 Cs-137 Cs-134 I-131 BG spectrum (before accident) BG spectrum (After accident) Detection Limit for gamma nuclides Many samples to be measured Contamination by radioactive plume Difficult to measure I and Cs in sample precisely Determine detection limit as 1/10 of concentration limit(CL) 131 I: 4 Bq/L, 134 Cs: 6 Bq/L, 137 Cs: 9 Bq/L

Radiochemical analytical method for Sr and Pu by Japan Chemical Analysis Center 9 Seawater 3L Carbonate separation Oxalate separation Ashing, dissolution Cation exchange Scavenging (removal of 90 Y) Leave over 5 days Milking with Iron hydroxides -> 90 Y( 90 Sr) measurement (60 min.) Milking with Carbonate -> Sr measurement (60 min.) Pu analysis procedureSr analysis procedure Seawater 1L Iron hydroxides separation Anion exchange Electrodeposition 238 Pu, 239,240 Pu measurement (1,300min.) detection limit 89 Sr, 90 Sr : 0.02 Bq/L, 238 Pu, 239,240 Pu : Bq/L

4. Radioactivity concentration in seawater and seabed sediment 10 Recognized direct release to sea Estimated atmospheric release In Bq11-16 March 131 I 134 Cs 137 Cs 1.6e17 1.8e16 1.5e16 In Bq1-6 April10-11 May 131 I 134 Cs 137 Cs 2.8e15 9.4e14 8.5e11 9.3e12 9.8e12

a) Front of NPP site 11 Seawater

Northern Side of the Water Discharge Canal of 5 and 6 BG level for 137 Cs before the accident=0.001~0.002 Bq/L 12 Seawater Cs-137 concentration limit of notification =90Bq/L Cs-134 concentration limit of notification =60Bq/L Bq/L MarchApril May June July 21~ 1,000, ,000 10,000 1,

Cs-137 limit =90Bq/L Cs-134 limit =60Bq/L May JuneJuly b) Near(~20km) site: Iwasawa Shore (15km south of NPP) Cs-137 limit =90Bq/L Cs-134 limit =60Bq/L MarchApril Bq/L 21~ 13 BG level for 137 Cs before the accident=0.001~0.002 Bq/L Seawater

In April, we collect samples on odd days, analyze and publish the results on even days. The following 2 sampling pattern would be conducted alternately. 14 Seawater c) About 30km from site (2)

In April, we collect samples on odd days, analyze and publish the results on even days. The following 2 sampling pattern would be conducted alternately. c) About 30km from site (2) 15 Seawater

d) + Neighbor prefecture July 25-31, Seawater 6 times at present DL: 134 Cs: 6 Bq/L, 137 Cs: 9 Bq/L

e) Deep sea 17 Seawater DL: 134 Cs: 6 Bq/L, 137 Cs: 9 Bq/L

Summery for the concentration of 131 I, 134 Cs and 137 Cs in seawater (in Bq/L) place 131 I 134 Cs 137 Cs a) Front of NPP site~180,000 (30, March) ~67,000 (7, April) ~68,000 (7, April) b) Near(~20km) site ---- coastal ~3,800 (28, March) ~1,400 (5, April) ~1,400 (5, April) b) Near(~20km) site km offshore ~920 (11, April) ~760 (11, April) ~760 (11, April) c) About 30km from site~161 (15, April) ~166 (15, April) ~186 (15, April) d) +Neighbor prefectureND(<6)~9.3 (11, May) ~11 (11, May) e) Deep sea-~12 (22, May) ~15 (22, May) Conc. Limit Conc. before the accident ND ~ (2010) 18

Sr and Pu concentration 19 Seawater Sr Pu

Summery for the concentration of 89 Sr, 90 Sr, and Pu in seawater (in Bq/L) place 89 Sr 90 Sr 238 Pu 239,240 PuCf. 137 Cs a) Front of NPP site~62 (18, Apr) ~7.7 (18, Apr) ND (<0.0005) ND (<0.0005) ~68,000 (7, April) b) Near(~20km) site ---- coastal ----~1,400 (5, April) b) Near(~20km) site km offshore ~69 (18, Apr) ~9.3 (18, Apr) ND (<0.0005) ND (<0.0005) ~320 (5, April) c) About 30km from site----~186 (15, April) d) + Neighbor prefecture----ND(<9) e) Deep sea----ND(<9) Conc. Limit Conc. before the accident ND~ (2010) ND ~ (Rokkasho, surface, 2010) ~ (2010) 20

21 sediment Plot of 134,137 Cs from 14.Jul to 10.Aug. U, Pu, Am, Cm: No influence from NPP Unit: Bq/kg from 9-14 May

22 Summery for the concentration of 131 I, 134 Cs and 137 Cs in sediment (in Bq/kg) place 131 I 134 Cs 137 Cs a) Front of NPP siteND(<30)~8,700 (14, July) ~9,600 (14, July) b) Near(~20km) site ---- coastal ~190 (29, April) ~1,700 (28, June) ~1,800 (28, June) b) Near(~20km) site km offshore ND(<13)~800 (26, July) ~870 (26, July) c) About 30km from site-1,200 (10, Aug.) 1,400 (10, Aug.) d) +Neighbor prefecture~6.1 (9, May) ~260 (10, May) ~320 (10, May) e) Deep sea--- Conc. before the accident ND ~1.4 (2010) 22

5. Plan for future marine monitoring Wider sampling area and lower detection limit by high resolution device Larger volume: 30~50L Chemical separation: AMP, coprecipitation of FeNi[Fe(CN) 6 ] Long counting time: 80,000 sec ～ 23 Sea areaDetection limit for 134 Cs and 137 Cs remarks Front of NPP~ 30km radiusNear NPP and coast: 1~2 Bq/L 10~30km from coast: 0.5Bq/L For a few point, MEXT will analyze them with the limit of Bq/L Coastal~ 30km from coast Off shore30~90 km from coast0.001 Bq/LBG level Deep sea90~280 km from coast0.001 Bq/L

24 Future monitoring map a) Front of NPP Seawater: 14 points Sediment: 14points ※ ※ With crosscheck b) Along the coast Seawater: 31 points Sediment: 20 points ※ ※ With crosscheck c) Offshore Seawater: 30 points Sediment: 30 points d) Deep sea Seawater: 21 points a) b) c) d) 24